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(No Model.)

R.- H. LAIRD.

PURNAGE.

No. 515,867. Patented Mar. 6 1894.

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UNITED STATES PATENT ROBERT H. LAIRD, OF TORONTO, CANADA, ASSIGNOR TO lWILLIAM HENRY i yLAIRD, OF NEW YORK, N. Y.

FU RNACE.

SPEEIFICATION forming part of Letters Patent No. 515,867, dated March 6, 1894,

Application filed March l5, 1893.

To a-Z whom imag concern:

Beit known that l, ROBERT H. LAIRD, of the city of Toronto, inthe county of York and Province of Ontario, Canada, have invented certain new and useful Improvements in Furrnaces; and I hereby declare that the following is a full, clear, and exact description of the same.

My invention relates to certain improvexe ments in furnaces and has for its object to provide a furnace of an improved construction whereby considerable economy is edected in the consumption of fuel, and wherein the combustion is so nearly perfect that almost I5 the whole of the carbon ofthe fuel is conn` verted Ainto carbonio acid gas, all as will be hereinafterfully described.

The novel features of my invention will be carefully defined in the claims.

In the accompanying drawing which serves to illustrate my invention I have illustrated in vertical anialsection a furnace constructed according to my invention.

In the drawing 5 represents the casing as a whole, said casing being composed of a lower or base-ring 5a, and a drum 5, surrounding the lire-pot, said drum having hollow walls forming a Water jacket thereabout as clearly shown. The interior'of this upper 3o drum 5b of thecasing or shell is provided with an opening or outlet cadapted for connection with the chimney at which opening the products of combustion pass off, and between the two sections 5a and 5" of the casing is ar- Y 3 5 ranged an annular diaphragm or partition 6 formed about the lower edge of an air'tube 8,

surrounding the combustion chamber or firepot 1, asseen in the drawings.

1LL is the grate, arranged at the base of the 4o fire-pot and 9 is a fuel magazine having a close fitting cover over its upper end, the lower end of said fuel magazine being open to the upper portion of the fire-pot in order to deliver the fuel thereto inthe ordinary manner.

The air tube Sis of asomewhat larger diameter than the fire pot 1, whereby an annular space sileft between the two and said air tube being of smaller diameter than the internal diameter of the drum 5b of the casing 5o a second annular space is left between said drum and air tube.

2, 2, are a series of radial draft iiues formed through the lower portions of the Walls of the lire-pot 1 and extending across the space between said fire-pot and the air tube and through said air tube into the space between the same and the drum 5" of the casing. The airtube 8 is closed at its upper end,but isin communication with the upper portion of the fire-pot l just below the fuel magazine by 6o means of apertures or perforations 7, 7, formed through the upper portions of the side walls of said fire-pot, and said air tube 8 is open at its lower end to the ash pit 4 of the furnace, from which it draws its supply of air as will be shortly described.

vMounted on suitable supports @,in the ashpit a just below the grate 1' is a steam pipe arranged `in the form of a ring or coil and provided with jets or nozzles d, d, arranged 7o at suitable intervals and adapted to admit steam into the lower open end of the air tube 8, and also y through the interstices inthe grate 1L into the lower portion of the fire-pot.

The steam so admitted greatly augmente the i draft and insures proper combustion of the fuel in the fire-pot although the same is not essential to my invention. A The operation of my improved furnace is as follows: The fuel magazine having been So charged and a fire kindled in the fire-pot at the lower portion thereof, the products of combustion arising from such fire pass out of the fire-pot through the radial draft fines 2, into the space between the air tube and the drum 5*? of the casing or shell, whence they pass through the outlet 5c to the chimney. The air required to support this combustion enters the dre-pot in part through the interstices in the grate bars la, andin part through 9o the perforations 7 in the upper sidewalls of the fire-pot after passing up through the air tube 8. Thus it will be seen that the products of combustion are drawn out sidewise or radially from the pointv of combustion through the dues 2, and the combustion is supported by two drafts, an upward draft through the grate and a down draft through the perforations 7, as indicated by the arrows in the drawing.

In furnaces, and especially in magazine furnaces and stoves as ordinarily constructed IOO heretofore, there has been a great waste of fuel owing to the heat from the burning fuel at the base of the tire-pot acting ontheY unignted fuel near the top of the lire-pot and in the magazine to decompose the same, whereby the various gases-hydrogen, carbon monoxide, carbonio acid, marsh gas,'oleflant gas, nitrogen, &c.,-which are evolved during the destructive distillation of the coal, dac., and some of which are very valuable for heating purposes, pass off with the products of combustion to the outlet of the shell and escape through the chimney. By my irnproved furnace, however, the escape of these valuable gases is prevented bythe down draft from the perforations 7 in the upper side walls of the tire pot, said down draft carrying any gases which may be produced by the heating of the fuel above the point of combustion, down to said point of combustion, where they are consumed as will be readily perceived. e

My invention is susceptible of considerable modification and therefore I do not wish to be understood as limiting myself to the precise construction and arrangement herein shown.

Having thus described my invention, I claiml. In a furnace, the combination with a shell or casing having an outlet for the gaseous products of combustion, of a fire-pot arranged in said casing, a grate arranged in said casing beneath the said fire-pot, an ai r-tube having a diameter greater than that of the fire-pot and having a less diameter than that of the casing, said air-tube being arranged in the space between the tire-pot and the casing whereby an annular air-flue is formed between the said air-tube and the fire-pot, and an annular gas-space or chamber is formed for the products of combustion between the said air-tube and the casing, said gas-chamber being in communication with the outlet to the chimney, said air-tube being closed at its upper end to said gas-space and having its lower end arranged below the grate, said fire-pot having a series of openings in the upper portion of its wall whereby air is supplied to the upper part thereof from beneath the grate, and a series of draft dues, the inner ends of which are open to the lower part of the fire-pot at or near the level of the grate said draft flues extending across said air-flue and being closed oif therefrom and having their outer ends opening into the annular gas-space outside the air-tube, substantially as set forth.

2. In a furnace, the combination with the shell or casing consisting of a base-ring constituting an ash-chamber, and a drum mounted above said base-ring and provided with an outlet for the gaseous products of combustion, of a fire-pot having a smaller diameter than said drum, said lire-pot being arranged in said drum whereby an annular space or chamber is formed between the said drum and fire-pot, said re-pot having in the upper portion of its side-walls a series of openings, an air-tube of a larger diameter than said tire-pot, said air tube having a closed upper end and being arranged in the annular space or chamber surrounding the firepot whereby said spa'ce is divided into two annular chambers, one of which is arranged between the said air-tube and the fire-pot and constitutes an air-fine, and the other of which is arranged between said air tube and the said drum and forms a gas chamber for the gaseous products of combustion, said gaschamber being in communication with the outlet of the casing, a grate arranged in said casing at the base of the fire-pot, said air tube having its lower end arranged below said grate whereby a current of air is supplied through said air iiue from below the grate through the openings in the upper part of the side walls of the fire-pot, the lower end of said air-tube being provided with an outwardly projecting annular yflange or ledge which is arranged between the base-ring and drum of the casing and closes the lower end of the annular gas-chamber in the shell, and a series of draft-fines having their lower ends adapted for communication with the interior of the fire-pot at or near the level of the grate, said draft flues passing across said air-tine and being closed od therefrom and having their outer ends adapted for communication with the annular gas-chamber in the shell whereby the gaseous products of combustion are drawn through said draft-fines from the point of combustion at or near the level of the grate outwardly into said gas-chamber, substantially as set forth.

3. In a furnace, the combination with a shell or casing consisting of a base-ring constituting an ash-chamber, and a drum mounted above said base-ring and provided with an outlet for the gaseous products of combustion, of a tire-pot having a smaller diameter than said drum, said tire-pot being arranged in said drum whereby an annular space or chamber is formed Vbetween the said drum and fire-pot, said fire-pot having in the upper portion of its side-walls a series of openings, an air-tube of a larger diameter than said 'tire-pot, said air tube having a closed upper end and being arranged in the annular space or chamber surrounding the fire-pot, whereby said space is divided into two annular chambers, one of which is arranged between the said air-tube and the lire-pot and constitutes an air-1l ue, and the other of which is arranged between said air-tube and the said drum and forms a gas-chamber for the gaseous products of combustion, said gas-chamber being in communication with the outlet of the casing, a grate arranged in said casing at the base of the fire-pot, said air tube having its lower end arranged below said grate wherebyacurrent of air is supplied through said air-flue from below the grate through the openings in the upper part of the side walls of the tire-pot,

IOO

IIO

the lower end of said air-tube being provided with an outwardly projeotingannula-r flange or ledge which is arranged between the basering and drum 'of ltbe easing and eloses the lower end of the annular gas-chamber in the shell, a series of draft-fines having their lower ends adapted for communication with the in-l terlor of the lire-pot at or near the level of the grate, said draft-dues passing across said airiue and being closed o therefrom and having their outer ends adapted for communica tion with the annular gas-chamber in the shell whereby the gaseous products of combustion are drawn through said draft dues from the point of combustion outwardly into said 15 annular gas-chamber, and a. steam-pipe arranged in the casing below the grate, said steam pipe being provided with a series of nozzles adapted to discharge jets of steam into the lower end of ythe annular air-due, whereby an upward draft of air is caused 'tol eirenlate therethrough, substantially as set forth.

Toronto, November 5, 1892.

ROBERT H. LAIRD.`

In presence of- C. H. RICHES, MARGUERITE ANGELL. 

